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Methicillin-Resistant *Staphylococcus aureus* (MRSA) Detection by Probe (Qualitative) in Whole Blood

Published: August 9, 2026Updated: August 16, 2026

This test checks for the presence of *Methicillin-resistant Staphylococcus aureus* (MRSA), a type of bacteria that can cause serious infections. MRSA is resistant to certain antibiotics, including methicillin.

Quick summary

["MRSA is a bacterial infection that requires careful monitoring and treatment with antibiotics that target it specifically."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
85786-2
Short code
mecA Bld Pos Ql NAA+n-prb
Synonyms
mecA Bld Pos Ql NAA+n-prb
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
non-probe-amp-tar
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may recommend this test if you have symptoms of infection—such as fever, redness, or pain—and have been exposed to MRSA. It’s also used in certain hospital or healthcare settings to prevent the spread of MRSA among patients and staff.

What Does a Positive Result Mean?

A positive result means MRSA bacteria were detected in your blood. This indicates an active infection that requires immediate medical attention and treatment with appropriate antibiotics. Your doctor will guide you on the next steps, which may include starting antibiotic therapy.

What Does a Negative Result Mean?

A negative result means MRSA was not detected in your blood sample at the time of testing. However, MRSA can still be present in other parts of your body or in your environment. If you have symptoms of infection, further testing or follow-up may be needed.

How Is This Test Performed?

A small sample of your blood is collected via a needle inserted into a vein, usually in your arm. The sample is then tested in a lab using a specialized probe to detect MRSA DNA or specific markers associated with the bacteria.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

MRSA Blood Screen (Qualitative)

Frequently asked questions

What are the possible side effects or risks of this test?
The most common side effect is a minor bruise, redness, or soreness at the injection site. Rarely, there may be a slight reaction to the needle. There are no known risks associated with the lab testing itself, but any blood draw can carry general risks like fainting or infection at the site.
How soon will I get my results?
Results are typically available within 24 to 48 hours, depending on lab processing times. Your healthcare provider will contact you directly with the results and next steps.
Can I take anything by mouth before the test?
Yes, you can eat and drink normally before the test unless instructed otherwise by your healthcare provider. Avoiding food or fluids for extended periods is not necessary for this test.
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy